Certain peptides are capable of self assembly when incubated in the presence of low concentrations of monovalent metal cations (U.S. Pat. Nos. 5,670,483; 6,548,630). Assembly results in the formation of a gel-like membrane that is non-toxic, non-immunogenic and relatively stable to proteases. Once formed, membranes are stable in serum, aqueous solutions and cell culture medium. They can be made under sterile conditions, are capable of supporting the growth of cells and are slowly digested when implanted in an animal's body. These characteristics make the membranes well suited as devices for drug delivery and as scaffolds for promoting the growth of cells in vivo.
In order to fully realize the biological potential of membranes, a method must be available for anchoring growth factors and therapeutic agents to the self-assembled peptides. Although compounds can simply be enmeshed in the peptide matrix, the highly permeable nature of the membranes will tend to lead to the rapid loss of such compounds in vivo. Ideally, factors should be attached to membranes in a way that is resistant to diffusion, that does not disrupt the structure of the membrane and that can be applied a wide range of compounds.